Immigrant children, many of whom have been separated from their parents under a new "zero tolerance" policy by the Trump administration, are being housed in tents next to the Mexican border in Tornillo, Texas, U.S., June 18, 2018. REUTERS/Mike Blake/File Photo

The U.S. government is moving some migrant parents to detention sites closer to the young children they were separated from while crossing the U.S.-Mexico border to meet a court-imposed deadline to reunify families, U.S. Secretary of Health and Human Services Alex Azar said on Thursday.

U.S. Judge Dana Sabraw in San Diego last month ordered the government to stop separating children from immigrant parents entering the United States illegally and set deadlines for the government to reunite families.

Sabraw set a deadline for children under 5 years old to be reunited by July 10, and all children by July 26. He also set a deadline of Friday for parents to be in phone contact with their children.

Azar said that based on a comprehensive audit by HHS and immigration authorities, there were now fewer than 3,000 children in HHS care who may have been separated from parents taken into custody for crossing the border illegally or for other reasons, such as concern over safety of the child.

Of those, approximately 100 children are under the age of 5, he said.

To speed the reunification process, the Department of Homeland Security is relocating parents of children under 5 years old to detention facilities close to their children "so that we can as expeditiously as possible reunite the children with their parents to meet the court's deadline," Azar said.

No children have yet been reunified with parents in the custody of Immigration and Customs Enforcement, but that will soon happen to meet the court deadline, Azar said.